[PATCH] Debug info: Cleanup collectChangingRegs

[Frédéric Riss]

On 06 Aug 2014, at 18:57, David Blaikie <dblaikie at gmail.com> wrote:

> The isDebugValue checking seems like a somewhat arbitrary case of
> pre-filtering.

It is indeed pre-filtering. I introduced it to match the corresponding test in calculateDbgValueHistory where the ChangingRegs array is checked only for !DbgValue instructions.

> Does it have an observable performance impact?

It was in the noise, otherwise I would have integrated it in the performance patch.

> Is there
> some more general test we can do here that would catch more cases of
> MIs that don't have register definitions? (to have a bigger impact and
> make the intent of the code clearer - it's not about skipping debug
> values, it's about skipping non-defining instructions)

That’s a question I asked myself. If this test exists, then it could go into calculateDbgValueHistory also to get bigger impact.

Fred